Pirlimycin

Pirlimycin is a lincosamide antibiotic specifically formulated for intramammary infusion in lactating dairy cattle. It is primarily utilized for the treatment of clinical and subclinical mastitis caused by susceptible gram-positive organisms. * **Key Pathogens**: Highly active against *Staphylococcus* species (including *S. aureus*, *S. epidermidis*, *S. chromogenes*, *S. hyicus*, *S. xylosus*), *Streptococcus* species (*S. agalactiae*, *S. dysgalactiae*, *S. uberis*, *S. bovis*), and *Enterococcus faecalis*. * **Clinical Pearl**: Unlike some older mastitis formulations, pirlimycin exhibits excellent tissue penetration, allowing it to reach deep-seated infections within the udder parenchyma rather than just remaining in the milk compartment. > **Note**: Organisms with a MIC of ≤ 2 mcg/mL are considered susceptible, while those with a MIC ≥ 4 mcg/mL are considered resistant.

Mechanism: Pirlimycin shares its mechanism of action with other **lincosamide** antibiotics (such as clindamycin and lincomycin). * **Mechanism**: Binds reversibly to the **50S ribosomal subunit** of susceptible bacterial RNA. * **Pathway**: Inhibits peptidyl transferase → prevents peptide bond formation → **interferes with bacterial protein synthesis**. * **Activity**: Generally considered **bacteriostatic**, but can be bactericidal at high concentrations against highly susceptible organisms. It is a time-dependent antibiotic.

VetSheet drug reference is intended for licensed veterinary professionals as a clinical decision-support aid, not a substitute for professional judgement or the manufacturer’s current label.